10.
21
All cement used on the works must be of uniform quality, and capable of Cement. bearing all the tests, physical and chemical, and to B.S. Specification No. 12, 1920.
Tests of each consignment of cement brought on to the site of the works will be made by the Engineer, and the Contractors must provide suitable approved modern testing apparatus, accommodation and assistance. The Contractors shall also provide a shed or suitable store, with boarded floor, on or near the Works, and shall arrange that a supply equal to 14 days' consumption shall always be in stock.
Should any cement be used in any part of the Works before a sample is tested and approved by the Engineer, the Contractors shall, in the event of the test being unequal to the Specification, remove at their own cost so much of any work that has been executed with such cement, as requested.
II.
The mortar used throughout the Works to be one part cement and two Cement Mortar. parts clean sharp sand, gauged and mixed dry, twice turned over, and afterwards incorporated with as little water as may be necessary to thoroughly saturate it. The mortar must be mixed on wooden platforms and used perfectly fresh, and no mortar which has become set will be allowed to be mixed up again.
12. The cement concrete used throughout the Works is to be of the proportions Cement Concrete. hereafter specified, of clean sharp sand and ballast or crushed granite, to proper gauges, from approved source; the cement and aggregate shall be thoroughly mixed together dry by turning over the materials completely at least three times, water shall then be added while the materials are again being turned over, until the water is thoroughly incorporated throughout the mass. The mixing shall be done on a proper mixing platform, and if a mechanical mixer be employed it shall be of such type as the Engineer shall approve. The concrete shall be deposited in its intended position in the Works as quickly as possible after mixing, and shall be thoroughly consolidated, and the whole so worked and placed in situ as to become one solid mass. If the concrete, when placed in position, be left exposed and becomes dry, unsound or dirty, or has been deposited 10 hours before another layer is added, it shall be cleaned off or washed down as may be practicable and necessary, and covered with cement mortar before another course is added. Where concrete has to be deposited under water, suitable and adequate means must be provided by enclosing in canvas or otherwise protecting, so that the concrete, once it has been deposited in position, shall not be disturbed or have cement washed out by currents or other causes, and rates must include for such contingency.
13. The pipes to be supplied are to be lap welded, of the best quality and Steel Pipes. workmanship throughout, of Stewart & Lloyd's or other approved manufacture.
All pipes must be truly cylindrical in bore, straight in the axis, free from twist, burr, upset or fin, and the ends must be cut truly square to the axis of the pipe, unless otherwise specified. The number of lineal feet of piping specified means the overall length as laid."
14. The pipes to be constructed of open hearth steel not less than -inch in Tests of Metal. thickness, made by the Acid or Basic processes having a tensile strength of 24 to 28 tons per square inch of section.
Tensile tests of the steel to show an elongation of not less than 20% in 8" with
a reduction in area at the fracture of not less than 45%-
Strips 11" wide to withstand being doubled over cold to an internal radius of
" with the sides parallel and without fracture.
15. The material to show the following analysis—
Carbon not to exceed
Manganese not to exceed
Silicon not to exceed
Analysis of Steel.
• 125%
* 54%
*035%
Sulphur not to exceed Phosphorus not to exceed
9753
*06% *06%
200
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